Does your data tell a story

The next time we hear that data is the new oil. Don’t think only in context of business. Data is the oil which is touching lives at a very personal level. This oil may not give tangible benefits like business expects. But it can have a lot of intangible benefits which potenitally can improve our well being. A few instances of data which we capture in our daily lives:

• The smart wearables captures a plethora of metrics. Some of them being, walking distance, resting heart rate, VO2 max, heart rate variability etc.
• The health check-up lab reports wherein we can see the vitals such as cholesterol level, sugar level, thyroid level etc. over a period of time.
• The digital bank statements of credit/debit card spend for several years. Also, the digital purchase of items on Big Basket, BlinkIt, Amazon, Flipkart and the likes.

These data are not just for the consumption of business but also for us. We can prepare charts based on the data generated by the apps and platforms. Some of the charts, say, health trends in smart wearables are easy to access. As data scientists and mostly with developer mindset, we tend to spend a lot of time building fancy charts using various packages in R and Python. Some of these charts like sunburst chart, heatmaps, tree maps shows the power of data visualization. Ofcourse, these charts help present data, succinctly. But at the same time, we seem to have mistaken data visualization as an art of just making fancy charts. The art does not lie in how succinct the chart is; the art lies in story telling with data. These stories are not in “What data shows” but lies hidden in “Why it shows, what it shows”? To build this point, we will analyze the health data (resting heart rate, heart rate variablity and VO2 max) of an individual captured by iWatch over a period of four years. It will be a real life story through the lenses of data. Something which business (including Apple Inc) can only wish they knew. The takeaways will be:

• In spite of seemingly being health conscious and hitting the gym regularly, why there is prevalence of heart attacks in younger generation.
• The story will break the myth about unhealthy eating and drinking being a stress buster as perceived by few amongst us.
• The hidden power of meditation and its impact on the function of human nervous system is too intense to be ignored.
• Why we cannot make a good analysis unless we spend a significant amount of time in understanding the data.

The point raised in first statement may need further corroboration. However, the insights from the analysis could potentially be used for taking actions to improve the lifestyle habits of individuals in general.

What is not a story

We will understand, “what is not a story”. But let’s first look at the idea behind Resting heart rate (RHR). We know that the normal average heart rate of the individual is 72 BPM. RHR is the heart beat per minute measured when the individual is inactive or relaxed for several minutes. Though apple watch documentation suggests that, it does not measure RHR during profound sleep cycle but the data capture time, suggests these reading being taken during night (a period of less activity). The lower the resting heart rate, the better the cardiovascular fitness level of individual. RHR can be improved by staying active, managing weight etc. Certain medication, like that of hypertension, keeps the heart rate low and thus the resting heart rate as well. Here is a simple plot which shows the resting heart rate of a person. It is a plot of longitudinal data as the data spans over a period of four year. The period of data capture is aggregated at monthly level over four years and thus making 48 observations (approx.). We can see the average heart beat for every year as well as the range in which the resting heart rate varied. It varied between 46 beats per minute (BPM) to 65 beats per minute over a period of four years. It hit the lowest in September 2020 and then there is a gradual increase, hitting a high of 65 BPM in December 2022. This is “What” data shows. But is this a story? Does it even generate any insight?

The insights would have come, had we labeled the periods of ups and downs with the life events of an individual. This is the hard part and is mostly missing in even the business level data visualization. This story (life event) can only be told by the person who was the subject of this data and not by people who plotted the observations in a fancy chart. We will unfold this life story later.

Before that, lets us look into yet another interesting metric reported by iWatch which is Heart rate variability (HRV). A normal heart rate of 60BPM does not imply that the heart is beating once every second. Within this window of one minute, there could be instance of 0.8 seconds between two beats and another instance of 1.5 seconds between the two beats. Intuitively, you can think of the two beats as two spikes in ECG and the time between the two spikes being 0.80 seconds or 1.5 seconds. HRV is measure of the variation in the time interval between beats. This HRV is measured by Apple watch using the standard deviation (sd) of beat-to-beat measurement i.e. sd of the values such as 0.80, 1.5, 0.1, 0.05, 0.46 etc. Higher the HRV the more relaxed the individual. Lower HRV depicts anxiety, stress. It generally varies between 60 milisecond - 80 milisecond, on an average, for a healthy individual. An HRV of 100 milliseconds (0.1 seconds) or more is considered exceptional. A value less than 50 milliseconds shows signs of anxiety and stress. Though it may seem that HRV will be more if resting heart rate is low but it may not be the case always. The HRV is also an indication of the stability of the nervous system. The chart shows the HRV trend but as was the case with RHR; we only see the whats happening. It does not tell any story.

VO2 max is a metric which measures the maximum amount of oxygen the body can consume while in period of intense exercise (say running/sprinting, hiking etc.). Higher the level of VO2 max, more is the cardiovascular fitness. It varies and generally goes down with age. The VO2 max of 35-45 mL/Kg/min may be considered average for a person in 35+ age group. The plot below shows how the VO2 max varied for an individual over time. The peak signifies the upteen level reached by the individual. But why it went down again? A pausible explanation could be drop in physical activity. But this is more of a speculation than the actual cause. The actual cause cannot be figured out in the plot.

What is a story

Every individual has a story to tell. Just that when we say it with data instances, the story becomes more convincing. So how do we tell such a story!!! We need to know the person and the life the person was leading i.e the subject whose life events generated the data. This is a story of a person whose name, co-incidentally, has got a lot of resemblance to my name (or may be more than just name:). Rahul is a guy working in software with a very ad-hoc work time. Work hard, party harder is the mantra with which he lives (not so uncommon in IT industry). But as is the case with any mid life IT professional, the work pressure, office politics, family chores keeps him on toes. The time to think about keeping track of health do come as a new year resolution but vanishes at equally faster rate.

But the penchant for tracking his vitals led to buying smart wearable. People do say that the apple eco-system is a trap and he closed the loop with an iWatch. The constant nudges from watch is enough to make one guilty of not doing anything. So, Rahul decided to hit the road. In December 2018, he joined the cardio fitness program. A rather intensive work routine of “Crossfit training” from 6-7 in morning; five days a week. It was a program which many could not sustain over few weeks. But the good part with him was, he continued going without being able to do most of the body weight exercises. It was embarrassing to not even do five push-ups. But this is when he realized how stale and unhealthy lifestyle he is leading. His admiration for people who could do endurance exercises went up several notches. It took more than 3-4 months of regular regime to come at level with some of the best in the group (but still left a lot of room for improvement). Within five months, the cross-fit seemed simple, the body flexible and his determination invincible. Ofcourse he started wearing the smart watch more regularly; like a maniac 24/7. The transformation not only led to making him more active but it reflected well on the attention span in work. This physical activity led to reaching a new height in the VO2 max.

The phase from May 2019 - Nov 2019 saw the peak in his endurance level. It proves a point on the effect of daily exercise on the fitness level. Not that, he left the exercise regime post Nov 2019 but the fitness level never reached the same level again. What went wrong? Nothing except the fact that he kept his party harder attitude intact. No amount of exercise is going to help sustain the fitness level, if not balanced with an equally conscious food choice. Ideally with the exercise routine, his RHR should have come down. But in the same period of May 2019 – Nov 2019, his RHR kept on increasing.

This happens when the body is stretched from two extremes. On one side, the cross-fit training and on other side, the constant intake of alcoholic beverage continued. The training made him feel active throughout the day, but he would wind up the day with unhealthy food and drinks. Thanks to the exercise routine which made him think that unhealthy lifestyle habits will not impact him. But the increase in RHR tells the story that rest was never profound. In the same time period, the HRV did not improve at all.

This puts across the point that while we may think, food and drinks helps release stress and anxiety, it does not seem to be the case. In spite of being physically active, the HRV paints a very gloomy picture. Overall we may conclude that increase in VO2 max, which reflects high level of endurance, was not accompanied by low level of RHR and high level of HRV (as desirable). But this is not the end of story. It becomes interesting now.

The news of covid started hitting India by Dec 2019. Not much of an impact at an individual level and things went on as normal till March 2020. But then comes the news of lockdown. This led to closure of cross-fit training and mostly everyone stayed indoor. March 2020 – July 2020 saw complete closure in India and we must have heard about the various cuisines people indulged in this lockdown period. Rahul was no different and tried his hands on cooking variety of dishes and tasted varieties of wine. All the above charts shows, how the health parameters deteriorated in this period. A phase wherein he still continued going for walk intermittently but more frequent was the consumption of alcohol and unhealthy food. It can’t be expressed on how bad a lifestyle he was leading. But the breaking point came on 1st August 2020. The morning wake up did not seem the usual one. Something was not right, the heart beat kept increasing, the breathing seemed difficult. To him, it seemed like a day which could be his last day. He kept a glass of water for over 45 minutes but was not able to even take the sip properly. He kept walking across the room with no clue on what is happening. He survived the day (though still have no clue on what happened) and went for a quick ECG. Things came out normal but the morning uneasiness continued to haunt. He could have been lucky to survive. But had something gone wrong, he would have come out as a fitness freak who died of heart attack. While he only knew that he was anything but a fitness freak.

For once and all, he decided to come out of all this. The next five months (August 2020 – Dec 2020) was a phase of recovery. A lot of medication started as many vitals were off track. But he knew that medicines alone will not help. In August 2020, he walked and ran a total of 335 Kms. He doesn’t know how he did this and he could never beat this mark. But he was determined enough to come out strong. In the next five months he covered a total distance of 1150 Kms (run+walk) which includes 100 kms run every month.

What happens when you do so? Well, the VO2 max, RHR, HRV all showed remarkable improvement. HRV went to 64ms by the end of August 2020 (a 13 units gain from July 2020). But why did it fall again when the same routine continued for five months? Have we heard about the issue with over-exercising. This is what happens when we over do the stuff. The body was not getting rest and it reflected the same with the drop in HRV for the next three months (inspite of rigorous 100 Km run etc). Nonetheless, the HRV of 64 ms by no means was a small gain (knowing that it is a heart parameter). The RHR for the first time dipped below 50 BPM. A lower RHR is a good sign but he did not expect it to go below 50 BPM. This started to look like a concern to him. A lot of research went in studying the phenomena and he realized that it goes down to 40 BPM for professional runners. But he was not a professional runner and when RHR started remaining low even while he was working; it looked very concerning. It occured to him that it could possibly be because of the medicine which he takes for hypertension for last 15 years. He consulted a cardiologist and it tuned out that he was on a very high dose of medication. He felt like going back to the physician who suggested him to change to this medicine in 2012 and give his piece of mind. But then in retrospection, what would have happened if he was not on this overdose of medicine and continued with unhealthy routine. Maybe he would not have lived to narrate this story to me. The BP medication dose changed and the vitals seemed to be reflecting a balanced lifestyle. April 2021, he had covid and it showed an impact on his RHR (increased) as well as HRV (decreased). He recovered within a week but covid had a lingering effect on the heart parameters. He could not continue his daily walk and run routine. But he realized a pattern; the RHR goes up and HRV comes down at least 1-2 days before one fall sick (an indication of a lag effect if someone is thinking about modeling for prediction of falling sick).

The damage done to the body may not be reversible completely but he continued to recover till April 2021 (with medication side by side). On the professional front, work kept him occupied as usual but an inclination towards getting into PhD program made him join a full time program at a prestigious B-School. Though covid kept classes in online mode but this journey started another phase in his life. A life which is equally stressful as job. In any profession it is difficult to maintain a balance and keep caring for one’s health. Rahul continued the sober lifestyle post August 2020 but this phase again hit him hard on the health. The constant pressure of study, assignments, quizzes, projects meant that the physical activity dropped. To the extent that between July 2021- Nov 2021, he averaged a walking distance of less than 100 Kms per month (< 3Kms per day). To put it in perspective, this is the amount of walk one does with the daily household chores. So consider this as good as not doing any physical activity. The mental activity kept increasing and physical activity kept going down. It all reflects in the RHR, HRV and VO2 max for the period July 2021 - December 2021. In spite of maintaining healthy eating habits, stress really reflects bad on the heart condition. A peak RHR of 65BPM, something which never happened even during unhealthy lifestyle (may be the overdose of BP medication), along with anxiety led to hospital visits twice in a span of two months (Nov 2021- Dec 2021). There is no medicine for it but to offload the work and balance with exercise routine. As he started with the routine, things started falling back in place. But as we see, vitals take time to return to normal. It took 2-3 months for RHR to come back to normal level. Imagine, the kind of stress we build with the work activities we get involved in. Since Rahul tracks it, he knows how these trends play out. But when it is not tracked, it reaches a breaking point and leads to unpleasant events. Body keeps sending signal, its about us to decide whether we want to act or ignore.

The PhD journey is a long one and it still continues. But with so many life lessons learnt and in quest for improving on his health, he thought of trying something new. End of April 2022, he joined a meditation program. As is the case with many, he also heard about meditation a lot but always shrugged it off as a mundane and monotonous activity. How can one sit for 20 mins with eyes closed and do nothing!!! It seemed like a task which can’t be carried on a day-to-day basis. Half heartedly he started this journey. But the result on HRV just caught him off guard. Within a month of practicing transcendental meditation daily, average HRV of 64 ms was hit without any rigorous physical activity. The last time this happened was August 2020 (a phase of 335 Kms run + walk). Sometimes during night and early morning the HRV breaches 200 ms mark. Something which never happened over a period of 4 years in which he started observing the trends. It just did not occur post this that he should stop meditation. The gain seems phenomenal. It is as good a gain as achieved while running 100Kms a month; which in no way was an easy task. The stress of PhD continues, the physical activity in terms of just keeping up the daily walk continues, eating healthy sometimes gets breached in a college life but the calmness which descends with meditation and its direct impact on the HRV as well as RHR seems much more than the virtues of meditation when explained subjectively.

The journey continues and he still has a long way to go in this PhD journey and in his life. But the story which he has lived through is worth a mention. For if you ever wear a smart watch and track your fitness goals, do try to relate back to the events which you went through at those times. It may lead to another interesting story. A story which may influence some individual to understand what it takes to follow a healthy lifestyle while continuing to work in the world full of chaos and uncertainty.

What if we plug our credit card spend data with the health metrics. We are pretty sure that it will lead to a richer story. But we keep that for some other day. The biggest takeaway is “Story telling through data is not about making fancy charts. It is about understanding the reasons why we see such a pattern. The reasons are the real learnings and can be used to take better informed decisions and actions”.

This story is published with due consent of the individual and I will be forever thankful to Rahul for giving life to data.